I’d say get what you want as long as you have some self control whilst developing your skills. My first bike was a 600 and it was very docile below 6k so commuting and running errands posed no real risk. Many of the 600 sports bikes are also quite light which means it’s easy to manage them. Out of them MT series I really enjoyed the MT09, lots of torque, fantastic motor although it can be a handful if you are ham fisted. .